Higher alkyl esters of chloromaleic acid



Patented Sept. 2, 1947 UNITED STATES PATENT OFFICE f HIGHER ALKYL ESTERSOF CHLORO- MALEIC ACID Raymond B. Seymour, Dayton, Ohio, a'ssignor toMonsanto Chemical Company, St. Louis, Mo., a corporation of Delaware NoDrawing.

This invention relates to esters of chloromaleic acid and alcoholshaving at least 8 carbon atoms and to methods of producing the same.

An object of the present invention is to provide I new and useful estersof chloromaleic acid. An-

other object of the invention is to provide new v COOY wherein Asignifies the group CH:CC1, X stands for an alkyl group of at least 8carbon atoms and Y is either the same as X or standsfor an aralkyl groupof from 7 to 9 carbon atoms, an alkoxy-substituted alkyl group of from 3to carbon atoms, a chlorine substituted alkyl group of from 2 to 4carbon atoms, an alkyl group of- -from 1 to 7 carbon atoms, or hydrogen.

As examples of chloromaleates having the above general formula may bementioned dioctyl chloromaleate, mono-octyl 2-chloromaleate,

'mono-octyl l-chloromaleate, bis(2-ethylhexyl) chloromaleate,mono-'(Z-ethylhexyl) 2-chloromaleate, bisU-methylheptyl) maleate,mono-(1- methylheptyl) 2-chloromaleate, mono-decyl 1- chloromaleate,mono-undecyl 2-chloromaleate, diundecyl chloromaleate, mono-dodecyll-chloromaleate, mono-hexadecyl 2-chloromaleate, di-

hexadecyl chloromaleate, dioctadecyl chloromaleate, 2-ethylhexy1alpha-chloro-beta-carbomethoxyacrylate, octadecylbeta-chloro-beta-carbobutoxyacrylate, dodecylbeta-chloro-beta-carbobenzyloxyacrylate, undecyl alpha-chloro-beta-(carbo-beta-phenylethoxy) acrylate, beta-chlorm ethylalpha-chloro-betacarbodecyloxyacrylate,

. gamma-chloro-propyl beta-chloro-beta-carbododecyloxyacrylate,beta-ethoxyethyl alpha-chlorobeta carbo 2 ethylhexyl) oxyacrylate,gammabutoxypropyl beta-chloro-beta-carbohexadecyloxyacrylate, etc.

Application November 10, 1943, Serial No. 509,768

2 Claims. (01. 260-485) As alcohols which may be employed'forpreparation of esters of chloromaleic acid containing at least oneesterifying group derived from an alcohol of at least 8 carbon atoms maybe mentioned n-octanol, iso-octanol, 2-eth ylhexanol, nonylalcohol,decyl alcohol, undecyl alcohol, lauryl alcohol, pentadecanol,cetyl alcohol, octadecyl alcohol, etc. Particularly useful are mixturesof higher alcohols obtained, for example, by hydrogenation of suchcommercially available fatty acids as laurlc acid (the commercialproduct known as "Lorol), stearic acid or oleic acid or the mixtures'ofhigher acids obtainable by oxidation of petroleum fractions. In generalsuch alcohols should contain between 8 and 18 carbon atoms.

By employing for esterification a mixture of alcohols, said mixturecontaining at least one of the higher alcohols selected from the abovelist, mixed esters of an improved type and unusual properties may beobtained. Suitable mixtures may consist of substantially equal molarquantities of two of the above-mentioned higher alcohols or a mixture ofmolar quantities of one of said higher alcohols and another alcoholselected from the group consisting of aliphatic alcohols of from 1 to 8carbon atoms, aralkylalcohols of from '7 to 9 carbon atoms,alkoxy-substituted alcohols of from 3 to 10 carbon atoms andchlorosubstituted alcohols of 2 to 4 carbon atoms. As examples ofalcohols which may be used with the present higher alcohols for theproduction of mixed esters of chloromaleic acid maybe mentionedmethanol, ethanol, tertbutyl alcohol, hexanol, benzyl alcohol,beta-phenylethyl alcohol, ethylene chlorohydrin, propylene chlorohydrin,ethylene glycol monomethyl ether, etc.

The present esters of chloromaleic acid range from clear, limpid liquidsto waxy or even crystalline solids, depending upon the nature of thealcoholic portion of the molecule. They are particularly useful in thepreparation of new, highly heat-resistant resinous or rubbery copolymersas disclosed in my copending applications, Serial the i to non H. .cooan. .0

wherein R is an alkyl group of at least 8 carbon atoms. The abovereaction takes place even atordinary room temperature, and inthe absenceof either a catalyst or a dehydrating agent. If an excess of thealcoholic component be employed,

the reaction product is usually a solution of the mono-ester in theunreacted alcohol. This shows that the reaction is unimolecular and thatunder the'mild conditions employed. no diesteriflcation occurs. Themono-ester, if solid at room temperatures, is thus readily obtained bycrystallization.

If it is a liquid, it may be separated from thecrude reaction producteither by vacuum distillation, solvent extraction, etc. For manypurposes,

especially for the preparation of'resinous or rubbery materials,isolation'of the mono-ester from the reaction product is not necessary.The reaction product, containing either the substantially puremono-ester or a mixture of the ester with the excess of alcohol oranhydride, depending upon the reactant quantities employed, may

be used as such for copoiymerizing reactions with a vinyl compound or adioleflnic compound or a mixture of the same.

If it is desired to prepare a di-ester from chloro-i maleic anhydride,subsequent esteriflcation of the initially formed mono-ester takes placeupon heating the mono-ester, preferably at refluxing temperatures, inthe presence of at least enough of the alcoholic component to allow'di-esteriflcation. Since reaction of the mono-ester with an alcoholtakes place with formation of water a dehydrating catalyst may beadvantageously employed in this step, or provision may be made forremoving reaction water, for example, by use of a water-trap. However,esterification of the mono-ester usually takes place so readily thatonly the application of heat is ordinarily required. The diesters maylikewise be prepared by esteriflcation of the free acid, by esterinterchange, or by dehydrohalogenation of the corresponding 1,2-dichiorosuccinates.

' The invention is further illustrated, but not limited, by thefollowing example:

Example A mixture consisting of one mol of chloromaleic anhydride and286 grams (2.1 mols) of 2-ethylhexanol was heated on a steam bath forone hour. At the end of this time formation of the mono-2-ethylhexylester of chloromaleic acid was substantially completed. In order toprepare the di-ester, 2 cc. of concentrated sulfuric acid and 50 cc. ofbenzene were added to the reaction mixture and the whole was refluxedfor a period of approximately hours in a reaction vessel equipped with awater-trap. During this time.

i 4 showed substantial completion of the esteriflcation. The excessalcohol was then distilled oil from the product under reduced pressure,and

the residue was washed with water, sodium carbonate, hydrochloric acidand then again with water. Water was removed from the product bydistillation with benzene, and after removal of the benzene the productwas recovered by distillation. There was thus obtained as a colorless goliquid the substantially pure bis(2-ethylhexyl) izhioromaleate, B. P,204-206 C./6 mm., n

The bis(2-ethylhexyl) chloromaleate may be advantageously employed inthepreparation of resinou materials, for example, by copolymerization withstyrene or other oleflnic compounds as disclosed in my copendingapplication, Serial No. 509,785, flied November 10, 1943.

Instead of 2-ethylhexanol I may employ other alcohols of at least 8.carbon atoms for the production of either the corresponding mono-estersor the corresponding di-esters of chloromaleic acid by the proceduredescribed above for the preparation of 2-ethylhexy1 hydrogen chloroggmaleate or the subsequent esteriflcation product,

bis( 2-ethylhexyl) chloromaleate. When preparing the higher esters,wherein either the alcohol or the product may be a solid, it isadvantageous to employ a diluent at the beginning of the .9 reaction inorder to bring about a smooth reaction.

In the preparation of such higher esters it is also preferable tooperate under pressure, for example, in a rotating autoclave.

As may be apparent to those skilled in the art,

88 the use of 2 mols of the alcohol per moi of the anhydrlde is notnecessary when the mono-ester isthe final product desired. Since theexcess of the alcohol acts as a diluent in the preparation of themono-ester, it is advantageously employed 0 even for the production ofthe mono-ester, and

in absence of such an excess of the alcohol it is desirable to employ anextraneous solvent or diluent. As solvents or diluents there may beemployed any liquid material which is inert under reaction conditions,for example, benzene, xylene,

petroleum ether, nitrobenzene, etc. The solvent or diluent should have aboiling point which is lower than that of the reaction constituents inorder to permit refluxing of the same.

As esterifying catalyst in the preparation of the diesters any acidicmaterial which is known to catalyze dehydrating reactions may beemployed. Instead of sulfuric acid I may use other mineral acids, forexample, phosphoric acid, or

55 such organic acids as the lower aliphatic carboxyiic acids or thearomatic sulfonic acids, for example, para-toluenesulfonic acid,benzylsulfonic acid, etc. Preferably, no catalyst isemployed in thepreparation of the mono-esters.

6 Esterifying catalysts and extraneous diluents or solvents are alsoadvantageously employed in the preparation of the diesters by reactionof chloromaleic acid with an alcohol of at least 8 carbon atoms. Wheneffecting the preparation of the as present esters by ester-interchange,for example,

additional diluent, depending upon the nature of the higher alcoholemployed.

The present higher esters of chloromaleic acid are particularly suitedfor the production of resinous copolymers with vinyl compounds because18 ml, of reaction water separated oil, which 15 they confer not only aheat-resisting property to '5 the final product but they also impartplasticity and consequent increase in toughness to the resinousproducts. Since the presence of the chlorine atom on the ethylene carbonappears to accelerate copolymerization, the present invention thusprovides for the synthetic resin industry materials which impartplasticity to a resin by ready incorporation of the same into theframework of the resin molecule.

While the present chloromaleates are particularly valuable for theproduction of synthetic resinous and rubbery materials, they are alsovaluable as intermediates in the production of a large variety of otherindustrially useful materials.

The chlorine atom and the oleflnic double bond of the chloromaleatesfacilitates the use of these esters for the preparation of surfaceactive agents, for example, by substitution of the chlorine atom by along-chain radical and subsequent sulfonation of the product at thedouble bond of the molecule. The higher chloromaleate esters maylikewise be advantageously employed for the preparation ofwater-repelling agents, for example, by reaction with alkyl amines,alkylol amines, ethylene I glycol, pyridine and formaldehyde, etc.

RAYMOND 1 3. ,SE'YMOtlR.

REFERENCES CITED The following references are'oi record the file of thispatent:

Walden, 'Zeitschrift fiir Physikalische Chemie, vol. 20 (1896) p. 380.

Havinga et al., Chemisch Weekblad," vol. 34

(1937), pp. 694-701. (Available inScientiflc Library.)

Tomas-Mamert,v BulL de la Soc, Chim. de France," Series 3, vol. 13(1895), p. 848.

